Question

我有一个imageView，我想将舞台当前位置以恒定速度移动到分割位置，无论距离如何。

尝试了下面哪些方法不起作用，我真的不知道如何根据imageView需要遍历的距离来保持动画持续时间的动态。

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
    if let touch = touches.first {
        let position = touch.location(in: self.view)
        print(position.x)
        print(position.y)


        CATransaction.begin()
        CATransaction.setCompletionBlock { () -> Void in
            self.imageView.layer.position = (self.imageView.layer.presentation()?.position)!
        }
        var animation = CABasicAnimation(keyPath: "position")
        animation.duration = 2


        var currentPosition : CGPoint = imageView.layer.presentation()!.position
        animation.fromValue = NSValue(currentPosition)
        animation.toValue = NSValue(CGPoint: position.x, (position.y))
        animation.isRemovedOnCompletion = false
        animation.fillMode = kCAFillModeForwards
        imageView.layer.add(animation, forKey: "transform")
        CATransaction.commit()




    }
}

Answer 1

试试这个

计算距离

func distance(_ a: CGPoint, _ b: CGPoint) -> CGFloat {
        let xDist = a.x - b.x
        let yDist = a.y - b.y
        return CGFloat(sqrt((xDist * xDist) + (yDist * yDist)))
    }

然后使用任意速度，计算时间

override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if let touch = touches.first {
            let position = touch.location(in: self.view)
            print(position.x)
            print(position.y)

            let distance = Double(self.distance(self.imageView.center, position))
            let velocity = 100.0 //pixels by seconds


            let time = distance / velocity

            UIView.animate(withDuration: time, animations: {
                self.imageView.center = position
            })


        }
    }

Answer 2

您可以添加imageView父视图的UITapGestureRecognizer并创建点按手势动作

@IBAction func tapGesture(_ sender: UITapGestureRecognizer) {
    print("tap working")
    if sender.state == UIGestureRecognizerState.recognized
    {
        let location = sender.location(in: sender.view)
        print(location)
        UIView.animate(withDuration: 0.5, animations: {
            self.imageView.center = location
        })

    }
}

将imageView从当前位置移动到以恒定速度点击位置

2 个答案: